Only download the offline installer from the official adobe.com or ardownload2.adobe.com domains. Avoid third-party "crack" or "download manager" sites that promise a "100% working offline installer"—they are often bundled with malware.
In this post, I’ll show you exactly where to find the official Adobe Acrobat Reader DC offline installer and how to install it without the web-based hassle. The standard download from Adobe’s main page is usually a AcroRdrDCx64_..._MUI.exe file that is only 1-2MB. That is not the full program. It is a download manager. When you run it, it pulls the actual 400MB+ of data from the internet. adobe reader dc download offline
What you need is the (also known as the full executable or the "Admin Installer"). Only download the offline installer from the official adobe